In the food processing industry, oxygen is reduced in the headspace of a package by injecting nitrogen, carbon dioxide or argon into the package to displace the air and, therefore, oxygen from the headspace. The reason for this is that oxygen adversely affects many food flavors and in particular vitamin C in fruit drinks. This replacement minimizes oxidation of the food stuffs to thereby substantially retard spoilage and increase the shelf-life of the packaged product.
In addition to nitrogen and argon, other antioxidants are known to prevent the oxidation of food, such as 14% bulyated hydroxyanisole, 6% propyl gallate, and 3% citric acid in ethyl alcohol for the protection of nuts.
More specifically, Buschkens et al Pat. No. 4,409,252 discloses a sequence of packaging steps wherein, after filling a container with a food product and covering same with a lid, the next step involves lifting one side of the lid slightly so that a protective gas, such as nitrogen, carbon dioxide, or argon, can be blown therein via a gas nozzle.
Bergstrom Pat. No. 3,481,100 advocates enclosing a container and a cover having one unclamped side in an evacuable chamber, evacuating the chamber and the container, introducing an inert or protective gas into the container and chamber, and hermetically sealing the cover.
Pohl Patent No. 4,448,011 discloses an inert gas wheel assembly including a shaft having axially aligned, apertured and oppositely rotatable wheels mounted thereon for introducing an inert atmosphere into a filled container.
Nishiguchi et al Pat. No. 4,805,768 includes a vertically suspended elevationally movable, cylindrical gas filling nozzle adaptable to being lowered into each container to inject an inert gas therein.